Auto Thumbnail app

Looking for a auto thumbnail of all images uploaded and added to a post... reason being im trying to get the it to work for when i send emails/mobile phone msgs to my boards, i have the inline lightbox, but im finding it impossible to find a auto thumbnail, that works automaticly, most have it within the blog editor, but that is to much of an hassle, i want to beable to blog on the go without having to worry about mega huge images on my blog..